Kendall and Kylie Jenner keep close with Robert Kardashian, their older half-brother as they arrive at KIIS FM’s 2010 Wango Tango concert held at the Staples Center in Los Angeles on Saturday afternoon (May 15).

The sweetheart sisters gushed about their new nephew Mason at the concert to OK! mag.

Kylie dished, “He’s amazing! Kourtney always comes over with him! Like, lately he just started rolling over, like onto his stomach.”

Kylie was also spotted with Kourtney, Mason and Scott Disick over the weekend in Malibu.